I have a 97 850 GLT (Turbo) and have an oil leak which I think was from an oil pan replacement I did a few months back.

I took the car in to the dealer today for a tranny flush/fluid change and they noticed the leak and said it was caused by a clogged PCV system. They quoted me $800 (canadian): $300 parts and $500 labour.

Also. I had previously noticed oil on the upper intake around the plug wires which I guess is coming from the oil cap.

OK here's the deal, I can think of better things to do with $800 so what can I do myself to fix/clean my PCV system (and change the right hoses etc)? Is there a PCV system on turbos?

The only parts you have to buy is the oil trap, there are two versions. The one you need depends on your engine serial # and FCP will ask for that. As for how to service the system, be glad I wrote this generic guide on how to do it. Things may vary a tiny bit based on the year of the car, but it's basically the same.

Ok, for some reason, Volvo likes to overengineer things and the PCV system is one of those things. Now, what you'll want to do is look down at the fresh air intake pipe right before the turbo. You should see something like what is in this diagram. Now, unplug all of those lines and check for clogging and clean as necessary. Sometimes, those lines are all that get clogged and you get off easy by only having to clean them out. Usually though, the problem lies deeper.

So, what you'll have to do is pull the intake manifold. You have a '95 model, which does have EGR, and makes the job a big pain in the neck.

Now, what you'll want to start with is unhooking the intercooler hose that goes to the throttle body and you'll also want to loosen the bracket that holds the hard IC piping over the engine. Then there are several other hoses that must be detached from the intake manifold up front on the driver's side. One of them is the evap valve hose and one is the CBV hose.

You'll then want to detach the hose from the Idle Air Control Valve, the silver cylindrical thing up near the manifold. That should cover all hoses that need to be removed.

Next, you'll want to unbolt the dipstick tube from the manifold. This one is tough to get to b/c you have to do it from underneath the car using a combination of long ratchet reaches to access it. I believe it's a 12 mm bolt. You can then just rest the dipstick tube against the fan shroud once loose.

Now back up top, you need to unhook the throttle linkage from the throttle pulley bracket using needle nose pliers.

I forgot to mention, you have to take off the plastic throttle cover, which is held in by a torx screw (T25 I believe) to get to the throttle area.

Alright, now you'll want to remove the throttle body, which is held in by four 10 mm bolts. If you're careful, you can re-use the TB (Throttle body) gasket that is already on there. Set the TB on the side.

Then, you'll have to undo the EGR bolts. There are two 8 mm bolts holding the EGR diaphragm to the intake manifold. I will warn you now that accessing these things is a big headache, but it can be done.

Once unbolted, the rest of the EGR assembly will just sit in the engine bay.

Now, to take the intake manifold off: I believe there are seven 10 mm bolts actually holding the manifold into the head. There is also a bracket down below that is tough to see that has to be unbolted as well. You can re-use the manifold gasket if you want.

Once pulled, you'll see a squarish black box on the passenger side (the rectangular black plastic thing on the driver's side is the starter). That box is the oil trap and is usually what gets clogged. It is usually replaced with a new part, which costs about $30 at the dealer. You'll want to remove all hoses going to it and verify that they're clear by blowing through them.

Here is a complete diagram of the PCV system and it's parts. It would also be a good idea to clean up the knock sensor connections while you have the manifold pulled. They're the two little black things with electrical plug-ins. Re-assembly is opposite of disassembly.

Added Diagram:

Last edited by White850Turbo on 01 Nov 2005, 15:27, edited 1 time in total.

This thread mentions diagrams but I see none. I have a S70 with some blow by around the turbo (not oil return line) and suspect the PVC system. I'd really like to know how to get in the tight place right over the turbo to take these lines off and then see if they're clogged. How do you do that....you can't get your head down there to blow through them.

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Thanks...was reading on the brickboard about how to get the hoses off of the main air hose from the MAF/Air filter box. It seems like a real pain. Any suggestions on that as well as how to get the clamps on and back on on the pcv's smaller hoses that come off of that. If the nipple is clogged, how do you recommend cleaning that? Is this stuff clogged really the reason for the blow by at that turbo?

Any tips for cleaning the knock sensor? Sorry, I'm not that mechanically inclined but can take apart and reinstall things if not too complicated. Would you use electronic cleaner, degreaser, or something else?

I also got a few new hoses with the PCV kit...I assume these all just slip on with no need for grease, etc?

my repair shop mentioned that they have alot of problems with 99's and up with clogged pcv's. they seem to think running synthetic helps this from occuring and is a reason they put synthetic in 99 and up maybe the same is true for earlier years.

For My '98 S70 T5, I paid only $110 for the pcv kit that fcpgroton sells. Evidently different than the 850's. I also (for $5.00) bought a intake manifold gasket, in case I can't get to the oil trap from below and have to take the manifold loose. I hope the parts come early next week so I can have this done before I leave for thanksgiving.